This is my first post to the forum so be gentle. I've gleaned alot of info from y'all and deeply appreciate all the expertise.

What method/recipe do you recommend for curing large, whole, bone-in, skin-on hams weighting 6-9kg? I will be helping slaughter 20 pigs over the next few months and dont know the specific weights yet.

I have used Hugh Fearnley-Whittingstalls cider immersion cure several times with good results but have come to learn that I am dancing with the devil regarding the risk of bone sour with large hams. Also, the brine is expensive.

I've noticed that most people are working with smaller cuts and that the brine calculators are not meant for larger hams.

Yes, I get to play with several hams. Thats alot of responsibility! I am leaning toward the Injection/Dry Rub Combination Brine Calculator using Saltpetre. This method does the math for me and allows me to hand off the hams to cure in peoples fridges after I have prepared them. (Space is an issue)

Anything left out of the beginners guide or calculator that you would like to add?

I have not decided upon a spice mixture. Anyone play with injecting liquids besides water? I have access to fresh pressed cider (non-alcoholic).

As you are planning on making more than one ham, I'd suggest you keep your first one simple. Focus on the basics, insuring you inject properly, deep into the muscle, use a good long needle for a full size ham such that you can get from the outside all the way to the bone. Insure you pump to a weighed percentage of the total weight of the ham. And I'd suggest just a simple cure, this will give you a base line such that you can then experiment with different techniques/brines, flavorings, etc. Keep good notes and weigh everything. Then in the future change perhaps one or two things at most, and test the result, it takes time to develop your technique and also your formulations. Making too many changes to process and or ingredients at one time will not tell you what works and what tends not to. I see a lot of folks starting with curing, or other forms of cooking, especially BBQ doing a lot of kitchen sink recipes, where they throw in about everything, not a good way to learn how to do curing, or in fact any type of cooking. Keep it simple at first and make slow deliberate changes from your notes as you modify a formulation to your final liking.